Project Summary/Abstract: This new Program Project will investigate the molecular mechanisms underlying the pathogenesis of bladder cancer. Our objectives are: (i) to study clonal evolution from non-muscle invasive to invasive to metastatic disease, and to elucidate molecular drivers for each stage of evolution; (ii) to study mechanisms of disease pathogenesis, with a major focus on the functional role of mutations that affect the epigenome; (iii) to elucidate mechanisms of disease response and resistance, with a major focus on understanding those that affect response to chemotherapy; and (iv) to generate novel human patient-derived and genetically-engineered mouse models (GEMMs) to study disease pathogenesis and to pursue co-clinical investigations. To achieve these objectives, we have assembled a highly accomplished multi-disciplinary team at Columbia University Medical Center (Cory Abate-Shen, Michael Shen, James McKiernan, Tian Zheng) and Memorial Sloan Kettering Cancer Center (David B. Solit, Hikmat Al-Ahmadie, Barry Taylor) with complementary expertise in genomic analyses (DBS, HA, BT), molecular investigations (CAS, MS, DBS), treatment response (CAS, MS, DBS, JM, BT), biostatistics and bioinformatics (TZ, BT), molecular pathology (HAA), generation of human and mouse cancer models (CAS, MS), co-clinical and clinical investigations (DBS, JM, CAS, JM, MS). We will pursue three interrelated Projects that are supported by three Cores. Project 1, led by David Solit, will seek to define the biologic functions of the histone demethylase, KDM6A, in bladder cancer pathogenesis, as well as the temporal occurrence of mutations in this gene during tumor progression. Project 2, led by Cory Abate-Shen, will analyze the functions of the chromatin remodeling gene, ARID1A, in muscle- invasive bladder cancer, focusing on its role in disease pathogenesis, its effect on treatment response and its molecular mechanisms of action. Project 3, led by Michael Shen, will investigate tumor evolution and drug response in human patient-derived bladder cancer organoids, focusing on genetic determinants of genomic instability, alterations of the epigenome, and the role of heterogeneity in drug sensitivity and resistance. The Molecular Pathology Core (Core A), led by Hikmat Al-Ahmadie, will maintain a biorepository of urothelial cancer tumors, including the tissues used for organoid generation, and will provide histopathological analyses for all three projects. The Bladder Cancer Models Core (Core B), led by Michael Shen will serve as a central hub for the generation and analysis of cancer models for all three projects, including human patient-derived organoid and xenograft models, and GEMMs. The Administrative Core (Core C), led by Cory Abate-Shen, will provide support for bioinformatic and biostatistical analyses and organizational support for Program Project investigators, and will coordinate with the Internal and External Advisory Boards. In summary, this Program Project is led by a highly collaborative team of investigators with diverse but complementary expertise who have substantial track records in cancer research, and are located in close proximity in New York City.